Researchers announced the oldest known fossil of the genus Homo, the evolutionary group of living humans. The new discovery, called the ‘Ledi jaw’ from Ethiopia, is 2.75 to 2.80 million years old. The lower jaw, known only from the left half, has smaller teeth than the ancestor Australopithecus and other similarities to later species of Homo, such as Homo habilis.

The most important jaw of Homo habilis, around 1.8 million years old, has now been restored. The shape was cracked as it fossilized. Using CT scanning, scientists could visualize and separate the cracked pieces to reconstruct its original shape. The newly restored jaw, found in 1960 in Tanzania, shows parallel rows of teeth like Australopithecus, yet it belongs to an individual with a large brain, similar in size to early Homo erectus.

The new reconstruction of Homo habilis (below, left) was published in Nature March 5, 2015, and the Ledi jaw (below, right) was announced in Science the same day.